[Qemu-devel] [RFC PATCH v1 0/3] spapr: Work around the memory hotplug failure with DDW

[Bharata B Rao]

Memory hotplug can fail when upcoming, yet-to-be-upstreamed, 2.7 feature DDW
is enabled. This happens due to a guest kernel bug which results in DDW code
in QEMU obtaining incorrect value of max possible memory address. This incorrect
max mem value results in incorrect DDW size which later causes hotplug
to fail.

While guest fix has been proposed, this patchset works around the problem
within QEMU. The workaround is described in patch 3/3. In summary this
patchset changes the alignment gap b/n RAM and hotplug region for pseries-2.7
onwards so that memory hotplug works with buggy guests when DDW is present
from 2.7 onwards.

v0: https://lists.nongnu.org/archive/html/qemu-ppc/2016-04/msg00226.html

Bharata B Rao (3):
  spapr: Introduce pseries-2.7 machine type
  spapr: Remove alignment gap b/n RAM and hotplug regions
  spapr: spapr: Work around the memory hotplug failure with DDW

 hw/ppc/spapr.c         | 92 +++++++++++++++++++++++++++++++++++++++-----------
 include/hw/ppc/spapr.h | 10 +++---
 2 files changed, 77 insertions(+), 25 deletions(-)

-- 
2.1.0